Circuit interrupter



CIRCUIT INTERRUPTER Filed May 8, 1953 4 INVENTORS THOMAS E. CURTIS FIGSJAMES M. deMONTMOLLIN BY M United States Patent CIRCUIT IN TERRUPTERThomas E. Curtis, Hampton, and James M. de Montmollin, Griffin, Ga.,assignors to Southern States Equipment Corporation, a corporation ofGeorgia Application May 8, 1953, Serial No. 353,742

11 Claims. (Cl. 200-114) This invention relates to circuit interruptersand more particularly to interrupters of the type commonly referred toas load break cutouts or fuses.

Electric cutouts which incorporate a fusible element disposed within afuse tube of insulating material are adapted for interrupting overloador fault currents by expulsion action in response to the melting of thefusible element and, if desired, load currents may be interrupted byphysically breaking the fusible element thereby to draw an are withinthe fuse tube which is extinguished by expulsion action in known manner.The circuit interrupting action may be accompanied by withdrawal of oneend of the fusible element from the fuse tube by means of an ejectorelement constructed of a low mass and provided with biasing meansarranged to effect a rapid withdrawal of the fuse link from the fusetube. Since the fusible element is commonly broken by means which ismanually operable and since fusible elements of high current ratings aredifiicult to break by ordinary manual means, a load break cutout isneeded which inherently is capable of breaking fusible elements of highcurrent ratings without requiring the operator to apply heavy forces tothe mechanism which tend to cause undesired stresses in and movement ofthe parts.

A principal object of this invention is to provide a load break cutoutwhich inherently is capable of physically breaking heavy fusibleelements of high current ratmgs.

Another object of this invention is the provision of a load break cutoutwhich is arranged to afford a substantial mechanical advantage so as toenable the operator to break large fusible elements mechanically withoutthe necessity of applying excessive forces to the device.

Still another object of the invention is to provide a load break cutouthaving a fuse holder which inherently remains substantially stationaryin its service position until after the fusible element is rupturedduring a load breaking operation.

The invention in one form as applied to a load break cutout comprises aconducting element pivotally supported by a fuse tube, an ejectorelement pivotally mounted on the conducting element, a fusible elementarranged so as normally to maintain the conducting and ejector elementsin their normal positions, and crank means for moving the ejectorelement out of its normal position relative to the conducting elementthereby to break the fusible element and allow the ejector elementpromptly to withdraw one end of the fusible element from the fuse tube.

For a better understanding of the invention reference may be had to thefollowing description taken in conjunction with the accompanyingdrawings in which Fig. 1 is a side view of a load break cutout embodyingthe invention, Fig. 2 is an enlarged view of a portion of the structureshown in Fig. l as seen from underneath with the parts occupying anintermediate position, and in which Fig. 3 is a detailed, enlarged viewof a portion of 2,737,551 Patented Mar. 6, 1956 Fig. 1 as seen from theopposite side of the device from that depicted in Fig. 1 with the partsin an intermediate position.

With reference to Fig. l the numeral 1 represents a support arm which atits left-hand end is mounted on a supporting structure (not shown) andwhich at its righthand end is secured to insulators 2 and 3. Afiixed tothe upper end of insulator 2 is a terminal element 4 which is providedwith openings 5 and 6 for cooperating with a longitudinally split bolt 7by which a conductor (not shown) may be secured to the terminal 4. Ahood 9 is pivoted at 10 to the terminal 4 for limited rotary movementand is provided with a latching surface 11. A brush contact 12 is alsosecured to the terminal 4. Latch 11 and contact 12 cooperate with themovable fuse assembly generally designated by the numeral 13 in a mannerto be more specifically described hereinafter.

A terminal 14 is aflixed to the lower end of insulator 3 and is providedwith a slot 15 which, as shown in Fig. 1, receives one portion of thelongitudinally split terminal bolt 16 for connecting the terminal 14with a circuit conductor (not shown). Terminal 14 is also provided witha pair of spaced extensions 14a between which the contact brush 17 ismounted. The spaced extensions 14a of the terminal element 14 areprovided with jaws 18 which cooperate with portions of the fuse assembly13 in a manner to be described hereinafter.

The fuse assembly 13 comprises a contact element 19 which is providedwith a contacting surface 20 for cooperating with the contact brush 12and is also provided with an upwardly extending latching portion 21which as indicated in Fig. 1 is engageable with the latching surface 11of the hood 9. Secured to the upper end of the contact 19 is a capmember 22. If desired, cap member 22 and contact member 19 may beconstructed in accordance with the disclosure of our application SerialNo. 338,836, filed February 25, 1953, and assigned to the assignee ofthis invention. It will be understood that insofar as the principles ofthis invention are concerned any known assembly arrangement could beused instead of the abovereferred-to structure comprising contact member19 and cap member 22. As is well known in the art, a fusible element isdisposed within the fuse tube 23 and is secured to the contact 19 at itsupper end and provided with a projecting portion 24 which extends out ofthe lower end of the fuse tube 23.

Afiixed to the fuse tube 23 by means of the screw 25 is a terminalelement 26 which is provided with an opening 27 therein for receiving aswitch stick or other operating member. Terminal element 26 is alsoprovided with a pivotal mounting 28 for the conducting element 29 whichis provided witha contacting surface 30 for cooperating with the brushcontact 17. The conducting element 29 is also provided with a projection31 which engages a portion 32 of the terminal element 26 when theconducting element 29 is in its normal position. Conducting element 29is maintained at its normal position by the conductor 24 which issecured to the conducting element 29 by the connector 33 which isscrewed into the threaded opening 34 in the conducting element 29 so asto grip the end of conductor 24 against the ridged surface 35 of element29.

The assembly 13 is pivotally mounted in the jaws 18 by means of a pin 36which interrelates the conducting element 29 with the trunnions 37 and38 which in turn are rotatably supported by the jaws 18. Trunnions 37and 38 are interconnected by an integrally formed oifsetl with a surface23a of conductingelement '29 whe'n the" parts occupy the positionsindicated in Fig"; 1 'Tl'ie -cirmii't' through the cutoutcomprises-terminal'14, brush contact 17 conduc tin'g'element 29,the-fusible element having the otit'wardlFeXfetidihg per tidmm} Contact1 9," bfu'sh conta a 1 2} and the: terminal 4.

Upon the' o'ceiinence of a" faiilt or overload c'o'nditioh on thecii'cnit controlled by the'devic'ey'th'efias'ime ele merit' disposedwithin the fuse tulie 23 melts-the ejec't'or' 40 under the 'aetien ofspring 41* promptly withdraws the conductor 24? and partsassociated-therewith frointhe ruse-tube 231 is eXTin'g'HiShe'Cl l byeXpulsion action in" known manner. During or immediately after this periodthe pivo't 28 mo've's" clockwise a'bout-pin 36' as'" a center from theposition indicated in-Fig "."l due to the weight' ofthe structure lfiand 't'oth'e biasing action of the brushcon taot 17.'Continuedrotationot 'pivot 28 abotit the pin 36- as a center eventuallycauses-downward motion of tite -upwardlyprojecting portion 21 'of'. thecontact- 1'9 therebyto disengage latching surfacelli Thereafter thewhole str'ucture liswing'sin a clockwisedirection about the t'ru'nriions37 and 38*andpin 3 6.=' Ihthis way an' isolating gap is establis'hed"between the terminals 4' ari'd lm The arrangement abovedescribed-isalso-adaptable a'ccording to this invehtionfo'r u'se" as adevice for iiiterrupt'in'g'normal load ciirrentjiir e; current whichisin sufficient in mag-nitude"tomelt the fusible element. Inf thisconnection it-will beobserved thafthe trunnions 3 7" and 38 and ofisetportion-39 are integrally formedwith a rnanl'iallyoperable handle'42which atits right-hand extremity is provided with'an opening 43' forreceiving the laterally projecting portion 44of a switch sticlc' 45;Thus withthe parts occupyingthe positions-shown-in Fig. la downward pullon the switch-stick45 causes the trun-' nions 37 and 38 and the offsetportion"3-9 to-move' in' a clockwise directionabout the-pin 36 Sincethe'olfset portion 39 'is in engagement with the eje'ctof'AO, the"ejector 4 is' forced to rotate in" a'clockwise direction" about thepin 36 as viewed in Fig." 15 Thus" a' itensiou forceisapplied to theconductor24-whichis sufiicienfto break the fusible element disposed witli'imthefuse tube 23i U on rupture of this element an" arc is drawn" andsubsequehtl it extinguished -by expulsion" tic'tioh-indihdwn manner. Thebreaking of the fusible element takes place" without causinganyappreciable-movementof' conducting eIementLZJ or of tub'e 2 3 accordingto a -featiire of the invention. For 'this rea'soh tlie latching surfacell sn'u'g ly' and securely holds the projectingportion' 21 of theconta'c't 1 9 in" a contact makihg position until ample op portunity"ha's'beenaifo'rded' to rupture the fusiblefele ment with in tube 23 andto extinguish the ar'cd'r'awn therein Thus 4 destructive arcs' betweencontact surface sible' to easily break-heavy fusibleelements oflar'gecurrenttratin'gs V I It-willb'e"observedthatiwhethertheconductingelement 2 occupies thepesitidnsliown in Figil ofwhether'th'e ejector element 40 andconductihgelement fihave been A 'ng ac is in such a direction as to tendto withdraw conductor 24fromthe-lower-end oftube 23.-

While we have shown and described a particular embodiment of theinvention, we do not wish to be limited thereto and intend in theappended claims to cover all such changes and modifications as fallwithin the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of theUnitedStates is:

1. An electric fuse comprising a fuse tube,. a fusible" element disposedin said tube and havingia por tion-thereof extending out of one end ofsaid tube;- a conducting element movably supported by said tubeand'having a normal position with resp'ectthereto, an ejectorelementmovably supported by said conductingtelernent and having a normalposition with respect thereto, said portion of said fusible elementbeing normally interrelated with said ejector element so as to hold saidejector element in its normal position relative to saidconducting'element and engageable with said ejector element for movwithbut movable independently ofsaidconducting element andenaggeablewith'said'ejector element for moV-- ing said ejectorelementrelative' to" said conducting element thereby to break saidfusible element;

2'. An electric fuse comprising a fuse tube, a fusibleelement disposedin said tube and having, a portion thereof extending out of one endofsa'id tube, a con-' ducting element movably'supported by said tube andhaving a normal position with respect thereto, an ejector elementmovably supported by'said conductingfleleinent and having a normalposition withrespectthereto, said portion of said fusibleelement'beingno'rmally interrelated with said conducting'and ejectorelements so asto hold: said'con'ductingand ejector elements in theirnormal positions, and manual means operably related with saidejectorelement and movable independently of 'said conducting, elementforengaging and moving said ejector element'outofits normal po'sitionrelative to said conductingelement thereby physically to" break said'fusible element.

3.'A'n' ele'ctric'fuse comprising a fuse tube a fusibleelement in saidtube and having a portion thereof extend:- ing out of one end of saidtube,'a conductingelement movably supported by said tube and havingflanormal position with respect thereto, an ejector element-pivotallymounted'on said conducting element and having a normal position withrespect thereto, biasingmeanstending tomove'saidejector element outof'its normal-position,

connector means for securing said portionof-saidfusible elementto saidconducting element so as to maintain said conducting element-in itsnormalpositionpsaid"portionof' said fusible element normally being inengagementwith said ejector element so as :normally-to hold said ejectorelement in its normal position: relative to said element disposedwithinsaid tube-and having one end+ thereof secured thereinand-havingtheother end thereof extending, out of one end of said-tube; aconducting element'secured by pivotal-support means to said tubeandhaving anormal position=with respect to s'aid tubeian ejectorelement'pivotally supported by saidcb'nd'ucting element and having anormal position with res ect thereto, connector means for securing saidother-"end of said fusible element to said conducting element thereby tohold said conducting and ejector elements" in their normal} positions,and manual means" interrelated hy, pivotal mounting means withsaid'cohduc'ting element and enga'g'eable' with said'ejector element formoving,,said ejectorelementout of its normal position relativeflto-s'aidconducting element and tube thereby physically to break said fusibleelement.

5. An electric fuse comprising a fuse tube, a fusible element disposedwithin said tube and having a portion thereof extending out of one endof said tube, a conducting element secured by pivot means to said tubeand having a normal position with respect to said tube, an ejectorelement secured by pivot means to said conducting element and having anormal position with respect thereto, said portion of said fusibleelement being interrelated with said conducting and ejector elements soas normally to hold said conducting and ejector elements in their normalpositions, a trunnion pivotally connected with said conducting elementand constituting a fixed pivot therefor, an offset portion movable withsaid trunnion and engageable with said ejector element for moving saidejector element relative to said conducting element thereby to breaksaid fusible element, and manually operable crank means movable withsaid trunnion and offset portion for imparting rotary movement theretothereby to impart operating movement to said ejector element.

6. An electric fuse comprising a fuse tube, a fusible element disposedin said tube and having a portion thereof extending out of one end ofsaid tube, a movable conducting element having a normal positionrelative to said tube, a movable ejector element having a normalposition relative to said tube, said portion of said fusible elementbeing normally interrelated with said ejector element so as to hold saidejector element in its normal position relative to said tube, a pair ofspaced trunnions interrelated with said conducting element by a pivotalconnection and interconnected by an offset portion disposed astride saidejector element and engageable there with, and crank means for rotatingsaid trunnions and offset portion to move said ejector element out ofits normal position thereby to break said fusible element.

7. An electric fuse comprising a fuse tube, a fusible element disposedin said tube and having a portion thereof extending out of one end ofsaid tube, a movable ejector element having a normal position relativeto said tube, said portion of said fusible element being normallyinterrelated with said ejector element so as to hold said ejectorelement in its normal position relative to said tube, a pair of spacedtrunnions interrelated with said ejector element by a pivotal connectionand interconnected by an offset portion disposed astride said ejectorelement and engageable therewith, and crank means for rotating saidtrunnions and offset portion to move said ejector element out of itsnormal position thereby to break said fusible element.

8 An electric fuse comprising a fuse tube, a fusible element disposed insaid tube and having a portion thereof extending out of one end of saidtube, a movable con ducting element having a normal position relative tosaid tube, a movable ejector element having a normal position relativeto said tube, said portion of said fusible element being normallyinner-related with said ejector clement so as to hold said ejectorelement in its normal position relative to said tube, a pair of spacedtrunnions interrelated With said conducting and ejector elements by apivotal connection and interconnected by an offset portion disposedastride said ejector element and engageable therewith, and crank meansfor rotating said trunnions and offset portion to move said ejectorelement out of its normal position thereby to break said fusibleelement.

9. An electric fuse comprising a fuse tube, a fusible element disposedin said tube and having a portion thereof extending out of one end ofsaid tube, a movable conducting element having a normal positionrelative to said tube, a movable ejector element having a normalposition relative to said tube, said portion of said fusible elementbeing normally interrelated with said ejector ele ment so as to holdsaid ejector element in its normal position relative to said tube, apair of spaced trunnions interrelated with said conducting element by apivotal connection and interconnected by an offset portion disposedastride said ejector element and engageable therewith, biasing meanstending to move said ejector element out of its normal position againstthe action of said portion of said fusible element, and crank means forrotating said trunnions and offset portion to move said ejector elementout of its normal position thereby to break said fusible element.

10. An electric fuse comprising a fuse tube, a fusible clement disposedin said tube and having a portion thereextending out of one end of saidtube, a movable ejector element having a normal position relative tosaid tube, said portion of said fusible element being normallyinterrelated with said ejector element so as to hold said ejectorelement in its normal position relative to said tube, a pair of spacedtrunnions interrelated with said ejector element by a pivotal connectionand interconnected by an offset portion disposed astride said ejectorelement and engage able therewith, biasing means tending to move saidejector element out of its normal position against the action of saidportion of said fusible element, and crank means for rotating saidtrunnions and offset portion to move said ejector element out of itsnormal position thereby to reak said fusible element.

11. An electric fuse comprising a fuse tube, a fusible element disposedin said tube and having a portion thereof extending out of one end ofsaid tube, a movable conducting element having a normal positionrelative to said tube, a movable ejector element having a normalposition relative to said tube, said portion of said fusible elementbeing normally interrelated with said ejector element so as to hold saidejector element in its normal position relative to said tube, a pair ofspaced trunnions interrelated with said conducting and ejector elementsby a pivotal connection and interconnected by an offset portion disposedastride said ejector element and engageable therewith, biasing meanstending to move said ejector element out of its normal position againstthe action of said portion of said fusible element, and crank means forrotating said trunnions and offset portion to move said ejector elementout of its normal position thereby to break said fusible element.

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